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22 Cards in this Set
- Front
- Back
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What are the general features of mites?
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-abundant, most free-living
-resemble ticks but smaller -lack rows of teeth on hypostome -have capitulum with palps and chelicerae -life cycle similar to ticks with egg, larval stage with 3 pairs of legs, nymphal stages (protonymph, deutonymph, tritonymph) and adults |
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What are the types of parasitic mites?
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1. Intermittent parasites - most of life cycle fee-living in nests or burrows, utilise blood as a food source
2. Permanent parasites - (a) on skin surface, feed on blood, live in ears, fleece, under scabs, nasal cavity or lungs (b) in tunnels in epidermis or in sebaceous glands |
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How do we classify Mites?
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- based on position of respiratory openings (stigmata) in relationship to coxae or legs/other features:
♦Metastigmata (= Ixodoidea) - stigmata posterior to coxae ♦Mesostigmata - stigmata between 3rd and 4th coxae -4 pairs of legs group at anterior end of body ♦Prostigmata - stigmata on capitulum, anterior to coxae -on head! -feather-like setae all over animal Astigmata - stigmata absent -front pairs of legs separated from back pairs |
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What pathogenic effects do the have on hosts?
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1. Blood feeding
2. Irritation due to bites often inducing hypersensitivity 3. Hair loss 4. Scab formation 5. Vectors of viruses and protozoans |
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What are some general features of the sub-order MESOSTIGMATA?
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-4 pairs of legs group at anterior end of body
-single pair of stigmata between 3rd & 4th coxae |
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What are the features, life cycle, effects on the host, & control of the genus Dermanyssus gallinae?
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Dermanyssus gallinae
✩FEATURES: -red mite of poultry -also found on birds, man, rat, & other mammals -triangular anal plate -parasite of birds & mammals -anal plate -blood feeders ✩LIFE CYCLE -life cycle : eggs, larva, 2 nymphs, adult -eggs laid in crevices and hatch in 2 days -larvae don't feed by nymphs and adults are both blood suckers -females lay eggs after 12-24 hours -life cycle 7 days -nymphs and adults rarely on birds during day, nocturnal ✩EFFECTS ON HOST: -anaemia -irritation -transmit Borrelia anserina CONTROL -control by removal of rubbish, and all shelter for the mites and spraying with 1% malathion |
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What are the features & effects on the host for Ornithonyssus spp.?
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Ornithonyssus spp.
Some important species: O. bursa, O. sylviarun ✩FEATURES: -common on wild birds -can bite humans -found in bird nests, can come down into house & bite you! -referred to as “starling lice” (because affect baby birds) -feed on birds while in nest -some on birds all the time -blood feeders -not host specific*** ✩EFFECTS ON HOST: -cause severe anaemia -reduced egg production |
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Which species do the following parasitise?
✩Pneumonyssoides caninum ✩Raillietia auris ✩Ophionyssus natricis ✩Sternostoma tracheacolum |
✩Pneumonyssoides caninum
-nasal mite of the dog ✩Raillietia auris -ear mite of cattle ✩Ophionyssus natricis -snake mite ✩Sternostoma tracheacolum -canary lung mite |
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What are the features of the sub-order Prostigmata? What genera are there?
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✩FEATURES:
-stigma on capitulum -feather-like setae ✩GENERA Trombicula Demodex Psorergates Cheyletiella |
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What are the features of the family Tombiculidae? What are the features of Trombicula sarcina & how do we control it? What does T. sarcina cause?
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-numerous genera in family Trombiculidae
✩FEATURES: -referred to as “trombiculids” -only larvae are parasitic -larvae are parasitic on animals & man, causing marked irritation -climb up on a blade of grass as larvae -attach in clusters, like tight places like waist-band or elastic line of sock, often seen on rodents -often yellow or orange -transmit scrub typhus (Rickettsia australis) -T. sarcina causes “black soil itch” in Qld -T. sarcina usually found on kangaroo, but may be seen on dogs, sheep, horse & man -seen after summer rains -cause leg itch in sheep -congregate between digits CONTROL: repellants & sprays |
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What are the features, localization, pathogenesis, 2 forms of the disease, diagnosis & treatment of Demodex canis?
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✩FEATURES:
-vermiform (wormlike) -legs very short at front of body ✩LOCALIZATION -live on hair follicles and sebaceous glands -feed on cytoplasm ✩LIFE CYCLE -egg, 2 nymphs, adults -all stages in hair follicles -infections occur at infancy during suckling -Host specific ✩PATHOGENESIS -Demodectic mange -all dogs infected -only some develop disease -short-haired dogs with CMI deficiency ie. dalmations -mainly 6-10 months of age -predilection sites eyes, ears, & muzzle Disease can be: A) Squamous form, localised or generalised, not secondarily infected B) Pustular (2°infection), localised or generalised -secondary infection with Staph. albus is common and leads to formation of pustules or to pyoderma -infection of follicles leads to hair loss & hyperkeratosis ✩DIAGNOSIS -deep skin scraping ✩TREATMENT -amitraz -ivermectin -can be difficult to treat |
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Describe the features, life cycle, transmission, seasonal occurrence, effect on host, diagnosis & treatment of Psorergates ovis.
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Psorergates ovis - "sheep itch mite"
✩FEATURES: -affects sheep in Aust., Africa, N. & S. America -tiny mite, 150 microns -each femur bears a large inwardly curved spine -lives in superficial layers of dermis ✩LIFE CYCLE: -egg, larva, 3 nymphs, adults -takes about 5 weeks -all life cycle stages are found on the surface or just below the superficial layers of the epithelium -nymphs and adults on surface but larvae and early nymphal stages may be under or in stratum corneum ✩TRANSMISSION: -contact (suckling from ewe to lamb, shearing) -predilection sites : sides, between hip & shoulder -near mid-line ✩SEASONAL OCCURRENCE: -most abundant in winter ✩EFFECT ON HOST -hypersensitivity causes irritation, rubbing, “pulled wool” -not all sheep affected -spreads slowly in mob ✩DIAGNOSIS -skin scraping ✩TREATMENT: -none, amitraz, OP’s, ivermectin; will not eliminate mites -just cull infected animals |
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What are the features of the genus Cheyletiella & the effects on the host?
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Genus: CHEYLETIELLA
C. parasitivorax rabbits C. yasguri dogs C. blakei cats ✩FEATURES -claw on palp -palpi are sort ✩EFFECT ON HOST -mild mange -often around head -can bite humans |
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What are the general features of Astigmata?
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- coxae 1 and 2 widely separated from coxae 3 and 4
- legs end in suckers claws or hairs, suckers pedicellate, pedicels maybe jointed - members of the family cause mange |
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What is a definitive host?
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Host where reproduction takes place
ie. Sarcoptes scabiei has dogs as definitive host |
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Describe the features, life cycle, pathogenesis, diagnosis, & treatment of Sarcoptes scabiei. What are some other Sarcoptes variants?
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✩FEATURES:
-triangular scales on dorsum wide host range -strains on specific hosts (eg. “var. canis”) can survive but not reproduce on other hosts -animal strains can live on man for short periods of time and cause a hypersensitivity reaction -long non-segmented pedicels and a terminal anus -transmitted from dog to dog or from wildlife reservoirs - wombat, foxes, ferrets ✩LIFECYCLE -lives in superficial layers of skin -lay eggs in tunnel or on skin -larva and 2 nymphal stages -life cycle 10-17 days -mites survive for few days off host -transmission by contact ✩PATHOGENESIS -burrowing mites cause irritation -nymphs and males mainly on surface -lesions begin on face, extend over body -hypersensitivity**** reaction to re-infection -commences on face (muzzle, ears) and then extends onto body -papules, swelling which is inflamed and intensely itchy -serum exudes and dries to form scabs following self inflicted trauma -hair may fall out -area damaged from scratching, intense pruritis -skin thickened & thrown into folds ✩DIAGNOSIS -skin scrapings -can be difficult to find mites ✩TREATMENT -most insecticides -leave housing free of animal for 2-3 weeks OTHER VARIANTS OF SARCOPTES ✩Trixacarus caviae - sarcoptid mite of guinea pigs ✩Notoedres cati - mainly on cats and rabbits ✩Notoedres muris- on rodents |
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What species does the genus CNEMIDOCOPTES infect and what lesions does it cause?
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Genus: CNEMIDOCOPTES
Life cycle similar to Sarcoptes Species : C. gallinae in feathers, depluming mite of poultry C. mutans on legs of chickens “scaly leg” C. pili on beak and legs of psittacines ✩FEATURES -legs very short -found on birds -causes thickening of scales of leg or scaly face |
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What genera do we have for the family Psoroptidae? What are some general features?
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-body oval
-legs 3 and 4 project beyond body margin -mites don't burrow, but cause scab formation -cause weepy lesions |
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What are the features, diagnosis, & treatment of Otodectes cynotis?
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Otodectes cynotis
✩FEATURES: -pedicels not segmented -common ear mite of dogs and cats also occurs in foxes and rabbits -causes scabs in external ear canal hosts shake heads and rub ears -transmitted by contact, often while suckling -may get fever & depression in cats ✩DIAGNOSIS -with otoscope, unreliable -examine exudate under microscope ✩TREATMENT -oral or topical insecticides |
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Describe the features, life cycle, & effects on the host of Psoroptes ovis
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Ps. ovis - sheep scab
-can also affect cattle ✩FEATURES -live under scabs and do not burrow -feed on tissue fluids, cause serous exudate ✩LIFE CYCLE -entire lifecycle spend on host -egg laid on host and hatch in 1-3 days -life cycle 9-10 days -larvae prick skin and cause serous exudate -high biotic potential (reproduces very rapidly & high numbers) -most abundant in cool weather -can have emaciation & high mortality eradicated from Australia ✩EFFECTS ON HOST -irritation, scabs, hypersensitivity -starts on shoulders and back, -spreads over whole body -in latent cases can occur in ears, inguinal folds, interdigital spaces |
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What are the hosts of Psoroptes cuniculi? What effect does it have on the host?
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Ps. cuniculi ear mite
✩HOSTS -hosts : rabbit, horse, goat ?alpaca ✩EFFECTS ON HOST -causes “ear mange” -may spread onto face -common in lab rabbits -causes irritation, shaking of head |
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What is the host of Chorioptes bovis and its effect on the host?
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Chorioptes bovis
-pedicels not segmented ✩HOST -in cattle, sheep, goats, horses occurs mainly on legs, belly -commonly seen in housed sheep & cattle ✩EFFECTS ON HOST -causes chorioptic mange -referred to as “barn itch” -can cause scrotal mange in rams |
